THE CONCRETE BRIDGE MAGAZINE

SUMMER 2016

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

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PA R T N E R S P O T L I G H T
26 | ASPIRE Summer 2016
DYWIDAG is celebrating a special
anniversary: 150 years. At this time,
we are looking back at the beginnings
of modern industrial construction
and reflecting on the extraordinary
achievements of DYWIDAG engineers.
These achievements continue to motivate
us to develop creative and technically
innovative solutions for construction.
Now, in the twenty-first century, more and
more daring architectural designs are
possible, and we know that this creative
power would have been unthinkable had
it not been for the development of new
concrete construction methods, from
precast concrete to post-tensioning.
It is difficult to appreciate today how
much technical knowledge and risk-
taking was needed to begin using
unreinforced concrete. This original
concrete was compacted by pressure
surges during pounding (compressed
concrete) in structures for which safety
had to be of the utmost importance.
1880—12-m (39 ft) Span in
Dusseldorf
One of the first concrete bridges in
Germany using this technology was
built by DYWIDAG in 1880. It was an
exhibition bridge with a 12-m (39 ft)
span that carried a pavilion and stood
on the premises of Dusseldorf's trade
and art exhibition. The demolition of the
bridge at a later stage was extremely
difficult due to the high compression
of the concrete. For a quarter century
thereafter, DYWIDAG built compressed
concrete bridges.
In 1922, DYWIDAG built a unique,
60-mm-thick (2.4 in.), 25-m-diameter
(82 ft) dome structure. Still today, the
construction material concrete is
constantly proving its superiority around
the world for shell construction and in post-
tensioning. Both construction methods are
inseparably connected with the name of
Dyckerhoff & Widmann AG (DYWIDAG).
1927—Saale Bridge Alsleben
In 1927, DYWIDAG was awarded the
contract for construction of the Saale
Bridge Alsleben, having designed an
innovative dual pivot arch rib structure
with stress ribbons. During construction,
the stress ribbons were first connected
with one side of the 68-m-long (223 ft)
arches and loosely positioned above a
recess in the middle of the longitudinal
girders for the bridge deck. Afterwards,
the stress ribbons were tensioned
using a newly developed puller until
they had reached their working load
and were then concreted. This project
represented the first important step
towards post-tensioned concrete.
The post-tensioning construction method
developed by DYWIDAG introduced an
innovative period for the construction
industry. Thanks to this method, it may
be said that concrete triumphed over
the laws of gravity and it was used
in new areas for the first time. Even
major bridges could be built using post-
tensioning and concrete instead of the
steel construction method.
1965—Pioneer Work and a
World Record
A convincing example for this
development is the Bendorf Bridge,
which crosses the Rhine north of
Koblenz, Germany. With a span of 208
m (682 ft), it was the world's widest
concrete girder bridge when opened in
1965. Even today, it is still fully functional.
Know-How for International
Projects
In the 1950s, in addition to its traditional
business area of construction,
DYWIDAG began signing license and
consulting contracts for the application
of the different DYWIDAG construction
methods around the world. The success
in post-tensioning was especially
helpful for DYWIDAG in this process.
This mainly applied to the following
areas:
• Bridges built using the DYWIDAG
Post-Tensioning System
• Construction of large bridges
using the patented DYWIDAG Free
Cantilever Method
• DYWIDAG Prestressed Concrete
Sleepers (Crossties)
In Europe, the DYWIDAG Post-
Tensioning System was mainly used
in conjunction with the free cantilever
method and the use of precast concrete
elements. The first projects were the
Freudenau Harbor Bridge and the
Au-Leistenau Bridge in Austria. In
Sweden, a large number of bridges
were built using the free cantilever and
precast concrete methods. Examples
include the bridge leading over the
Kallosund near Skagerrak with a main
span of 94 m (308 ft), which was
completed in 1957. Additional license
agreements were signed in Denmark,
Finland, Norway, and the Netherlands.
150 Years of
Bruecke-aus-Stampfbeton made of high-compression concrete.
by Dave Martin, DYWIDAG-Systems International USA Inc.